Quick question, i think i even figured it out but just wanted to get some input and make sure i do have the answers.
So i just installed 8 fogs on my roof rack, 4 50watt and 4 100watt. yes overkill lol.
Now, i wired them in a series circuit, which is where i think i messed up. theres a point where the gauge in between a few lights is pretty small. now, all the lights light up when i turn them on but their verrrrry dull. just kinda glowing.
im assuming i have to go with a parallel circuit, only question is what gauge wire should suffice for the supply wire part of my circuit.

 

Firstly, are they wired with relays? If not, they should be done this way. I'd run minimum two seperate lines with 2 switches, 4 lights on each, but two lights per switch/relay would be what I'd go with. From there you can set them up to turn on which sets you want seperately, I'd use 8guage wire for the wiring for the relay and lights, but you could go a lighter guage for the switches as it just triggers the the relay. Hope this helps.

Cheers!